the leader of the kurdish pkk rebel group has told the bbc that they're willing to disarm under un supervision if the turkish government meets certain demands. they are listed as a terrorist organization by most western governments. for years they have attacked targets in turkey from inside iraq. our correspondent traveled to kurdistan to meet the leader. >> somewhere in the mountains, the fighters are training. this video, film by the group itself, showing one side of a conflict that has claimed the lives of around 40,000 people on both sides. turkey says that these men are terrorists. the u.s. and european union agreed. here's why. this attack on the bus in istanbul killed five people, four of them soldiers, one of them a 17-year-old girl. a splinter group has admitted to carrying out the attack. this has been going on for 26 years. we were invited to witness a camp at a secret location in the mountains. the fighters were not keen to be filmed. for more than one decade they have used these mountains as a base from which to plan and execute attacks inside turkey. justifying killing in the nam